Shin-Ei Uni-Vibe

Though we like to think of the Cabinet as our own tiny museum of musical ephemera, it is certainly no expertly curated collection. While we love each and every piece, the same can not be said of all its viewers. Some such artifacts go unappreciated by all but the hardiest pedal aficionados. However, only three effects that I personally know of are part of an actual museum exhibit, positioned for patrons to recognize their contributions to music as a whole. These three pieces are the pedals of one Jimi Hendrix, and they are the Cry Baby wah, the Arbiter Fuzz Face, and this week’s entry—the Shin-Ei Uni-Vibe.

Fumio Mieda is the inventor of so many pieces of classic musical equipment that it should come as no surprise that the Uni-Vibe is another one of his classics. What many people don’t know, however, is that Mieda’s original creation wasn’t called the Uni-Vibe, instead it was a “Mood Adjuster” effect found in the world’s most valuable effects unit, the Shin-Ei Psychedelic Machine.

When Mieda conceptualized what we now call “vibe” in the late ‘60s, his vision was that of Russian radio stations transmitting sounds across frequency bands, intermodulating them and then broadcasting them at the receiver end, and so Mieda sat out to recreate the Doppler effect within the bounds of a handful of parts. He found this to be a very “psychedelic” sound and so it sat sidesaddle with a “Fuzz” and became the Psychedelic Machine.

Both Psychedelic Machine sections garnered legions of followers, and the individual effects proved so popular that Mieda quickly adapted each to stompbox use. The Fuzz section became the Univox Super Fuzz, while the Mood Adjuster became the… Vibra Chorus?

Yes, early versions of the Uni-Vibe are called the Vibra Chorus and the “Resly Tone” (yeah). It wasn’t until a short time later that the pedal got an aesthetic overhaul and became the Uni-Vibe we know today. But not before Jimi had his way with one onstage at Woodstock; that’s when savvy players, producers and engineers began hoarding them, and the ‘Vibe went worldwide.

If you’ve ever struggled to explain the concept of pedals to a loved one, rest assured the full thrust of the Uni-Vibe relies upon an actual pedal—finally, something for you folks to talk about at Thanksgiving. A separate foot controller hooks right into the front, allowing you to vary the speed or even turn the thing off—a handy feature, since the Uni-Vibe contains no actual bypass function. It does have a fuse holder up front, though!

Two modes of operation are available—Chorus and Vibrato. It is important to note that it’s actually the Chorus setting that people associate with Hendrix and Trower, and not so much the Vibrato mode. Ready to get your mind even further knotted up? The Uni-Vibe, as so eloquently conceptualized by Mieda as a real-time automated phase-shifting circuit, is just that—a phase shifter, or as we colloquially refer to it, a phaser.

Yes, you read that correctly. Now to see what makes a Uni-Vibe a Uni-Vibe, and not, say, a Phase 90, it’s important to understand just what makes it tick.

Aside from all the transistors, strange power requirements and all other components, you’ll notice one particular section on the Uni-Vibe board that looks a little odd even today, in an age where we’ve figured out how to make guitars sound like cartoon characters. Five components form a shrine-like apparatus in the center of the board—at least that’s what you would see, if you pried the silver box from the board as well.

Inside this box is the heart of the Vibe. A single incandescent bulb is surrounded by four light-dependent resistors (LDRs), with each oriented in the vicinity of the bulb; the more light each sees, the lower the resistance. As the lamp illuminates in a rhythmic fashion, it biases four different sections of the circuit simultaneously, as the light reflects off the lining of the silver “hood” piece. You could accomplish the same feat with four potentiometers, if you could turn them all at the same time. Several factors including differing part tolerances line up to spit out a phase shifter with a reverse-sawtooth LFO—key to that rhythmic throb that you can feel in your chest. This is how the Uni-Vibe earns its keep.

It is this arrangement that generates the most controversy in the world of the Vibe, and as you might expect, the unit is not without its purists. Some folks claim that unidirectional LEDs can do the same trick, so long as each LDR gets its own LED. However, others claim that a Vibe is only a Vibe if it uses the exact same arrangement as the Shin-Ei: a metal hood with a mirror-like interior, an incandescent bulb and four LDRs. I’ll tell you one thing: You play one lick through an original box, and after your heart slows down, you’ll be inclined to agree with the latter.